Patent GB-322493-A (GB)
Title: Improvements relating to the production of kinematographic combination pictures
IPC: G03B15/12
Filed: 1928-09-06
Abstract: 322,493. K÷hler, W. Sept. 6, 1928. No Potent granted (Sealing fee not paid). Composite kinematograph picture films are produced in one taking operation of the camera. by recording a background with the actors and/or foreground in silhouette and the actors and/or foreground with the background in silhouette, a scene being considered in silhouette when it is so illuminated or so photographed through colour filters as to be actinically ineffective. In one form, in which the two records are photographed on one film in succession, a film 14, with background pictures and transparent spaces in alternate image fields, and a normal unexposed film 15 pass through the film gate 18 together, but the film 14 is advanced twice while the film 15 is advanced once. In front of the camera is a plain screen 19 illuminated by lamps 21 and having a horizontal extension 20 on which the actors 22 illuminated by lamps 23 perform. When a picture element of the film 14 is in the aperture 13, the lamps 23 are switched off and the lamps 21 switched on. The rotary shutter 12. opens, and the film 15 receives an image of the background picture on the film 14, the actors being represented by unexposed parts. The shutter closes and the film 14 moves onwards bringing a transparent portion into register with the aperture 13. The lamp 21 is then switched off and the lamp 23 switched on. The shutter opens and an image of the actors is thrown on to the unexposed parts of the film 15, producing a complete picture. The shutter then closes, the films 14 and 15 move onwards together and the operation is repeated. The lamps 21, '30 and 23 are controlled by switches or shutters regulated by the sprocket 14a. Alternatively, the screens 19, 20 and the actors are continuously illuminated by differently coloured lights, and the alternate exposure is effected by a rotary colour filter. A semi-transparent mirror 25 and a reproduction of the background picture at 24 enable the place of acting of the actors to be determined. A mask 28, having an opening 29 exposing only so much of the field as is used by the actors, is placed near to the camera and illuminated so that its actinity corresponds to that of the screen 19. To avoid damage caused by passing two films through the same exposure aperture, they may be spaced one behind the other, transmission being effected by a lens combination. In a modification, the camera has two exposure apertures. The films 15 and 14, the latter in this case having pictures directly following each other, pass together through the first aperture and are exposed while the screens 19, 20 are actinically effective. The film 15 then passes alone to the second aperture and is exposed while the actors are actinically effective. Two further forms of apparatus are described in which the film 14 is arranged outside the direct path of the light from the actors to the film 15. Light from the screens is projected through the film 14 and on to the film 15 by a system of semi-transparent reflectors, whilst light from the actors is projected directly. In a further modification, the two records are taken on separate films, a completed positive being obtained by copying the two films together. Two cameras side by side may be used; in one a record of the background is taken, the actors being excluded by colour filters, and in the other the actors alone are taken by using a semi-transparent mirror system. When the film 14 is not available, models of the background are placed at 24, illuminated by coloured light, and reflected by a semi-transparent mirror 25 into the camera. The actors are illuminated by light of a different colour, and are photographed directly by a second camera. It is stated that the transmission of light from the actors through the mirror in front of the first camera disturbs its power of reflecting the models, so that on inserting between the mirror and the camera a filter which only transmits light from the models, a picture is obtained in which the parts to be occupied by the actors are unexposed. In this method, strong shadows on the actors may be illuminated by light of a third colour which is not recorded but which is stated to destroy the reflecting power of the mirror 25. To enable the actors to be conveniently positioned in the studio, magnifying or reducing lens may be placed in front of the camera lens.